Japanese Laid-Open Patent Publication No. 2002-149244 discloses a fluid supply apparatus which includes a parallel passage section where passages are connected in parallel. In the above fluid supply apparatus, a working fluid in an automatic transmission is supplied to a radiator and a thermal storage tank to perform heat exchange, and the working fluid that has been subjected to heat exchange is returned to the automatic transmission. Also, in the fluid supply apparatus, a conduit connected to the radiator and a conduit connected to the thermal storage tank are connected in parallel with each other. A selector valve is operated to shift between a state in which the working fluid is supplied to only the radiator and a state in which the working fluid is supplied to both of the radiator and the thermal storage tank.
In the above mentioned fluid supply apparatus, when the number of passages through which fluid passes in the parallel passage section is changed in accordance with the operating state of the selector valve, the following drawbacks may occur.
That is, when the number of passages through which fluid passes in the parallel passage section is changed, the total cross-sectional area of the passages through which fluid flows is changed, thus changing the pressure loss at the parallel passage section. When the pressure loss at the parallel passage section is changed, the flow rate of fluid in the parallel passage section is also changed, which also changes the flow rate of fluid in the entire fluid supply apparatus.